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<a href="detail_2util__fwd_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
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<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
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<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="string__view_8hpp.html">flow/util/string_view.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="preprocessor">#include &quot;<a class="code" href="common_8hpp.html">flow/common.hpp</a>&quot;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="preprocessor">#include &lt;boost/shared_ptr.hpp&gt;</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="comment"></span> </div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="comment">/// @cond</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="comment"></span><span class="comment">// -^- Doxygen, please ignore the following.</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span> </div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment">/* This strangeness is a work-around a Boost bug which manifests itself at least in g++ and clang++ in</span></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment"> * C++11 mode, when trying to use ratio&lt;&gt;::num and ::den.  Without this, those two symbols, per each ratio&lt;&gt;</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"> * type directly used, each get an undefined reference linker error.  See https://svn.boost.org/trac10/ticket/13191,</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment"> * not fixed as of this writing.  @todo: Revisit. */</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="preprocessor">#ifndef BOOST_NO_CXX11_CONSTEXPR</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="keyword">template</span> &lt;boost::<span class="keywordtype">int</span>max_t N, boost::<span class="keywordtype">int</span>max_t D&gt;</div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="keyword">const</span> boost::intmax_t boost::ratio&lt;N, D&gt;::num;</div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="keyword">template</span> &lt;boost::<span class="keywordtype">int</span>max_t N, boost::<span class="keywordtype">int</span>max_t D&gt;</div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="keyword">const</span> boost::intmax_t boost::ratio&lt;N, D&gt;::den;</div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="preprocessor">#endif</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span> </div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment">// -v- Doxygen, please stop ignoring.</span><span class="comment"></span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment">/// @endcond</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"></span> </div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1util.html">flow::util</a></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span>{</div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span> </div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span> </div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment">/* (The @namespace line shouldn&#39;t be needed, but there must be some Doxygen bug causing that doc header to get</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> * merged into the succeeding function&#39;s.  Who knows?  @todo Look into it more in copious spare time.</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> *</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> * Update: That was with Doxygen 1.8.11 through 1.8.15.  In 1.8.16, it&#39;s still true; plus another bug appeared:</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> * The first sentence (up to the first period) is supposed to interpreted, with certain Doxygen config,</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> * as @brief, meaning the brief summary of the namespace; this feature is used constantly, not just in this</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> * spot.  Well, for some reason that Doxygen version took the @brief to be blank (shows up as blank in the</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> * namespaces list page and the namespace page itself), whereas before it was fine.  Since it&#39;s not happening</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> * for anything else I made it an explicit @brief here and called it a day; I guess the Doxygen parser is</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> * getting doubly confused; not sure.  @todo Sigh, untangle this at some point; maybe Doxygen gets fixed;</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> * file bug against Doxygen.  This is the only (documented) namespace alias in the code, as of this writing, so</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> * maybe that is why it is &quot;special.&quot;) */</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment"></span> </div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment">/**</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno"><a class="line" href="namespaceflow_1_1util_1_1bind__ns.html">   61</a></span><span class="comment"> * @namespace flow::util::bind_ns</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> *</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> * @brief Hack namespace alias to enable use of `bind` and related utilities like `cref` in the face of strange observed</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment"> * compiler behavior.</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"> *</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment"> * The code in the past used `bind` and its helpers `cref` and `ref` fairly extensively.  (Vast majority of `bind`s are</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"> * now replaced with superior uses of lambdas, with the upgrade to C++1x.  So it&#39;s far less extensive than in past.)</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"> * However, there is something odd going on with namespace resolution for</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment"> * these guys.  At least in the clang version used as of this writing, `bind` somehow</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"> * works without qualification, as does `cref` (and thus probably `ref`); I really don&#39;t know why.  I&#39;d like to use</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment"> * the `boost::` versions, though, specifically (for stylistic reasons explained elsewhere).  More importantly, I don&#39;t</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> * want to use something that mysteriously works without qualification -- is `std::` somehow being forced with some</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> * phantom `using namespace` from some evil header somewhere?  I am not sure as of this writing.  In any case,</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> * this allows one to just say `using util::bind_ns::bind` and then use `bind()` without qualification in that</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> * block (typically function/method) without worrying that some weird unqualified guy will be used.</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> *</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> * Caveat 1: I don&#39;t know why, but in the aforementioned clang, `using util::bind_ns::cref` makes `cref()` become</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> * ambiguous with some `std::cref`; it&#39;s quite unclear why the same complaint then doesn&#39;t happen for `bind()` itself.</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> * In that case, when an error is encountered, get rid of the `using` and instead qualify it as `util::bind_ns::cref()`.</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> * It sucks, but at least it&#39;s clear.</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> *</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> * Caveat 2: I haven&#39;t built in MS Visual Studio in quite a while (though it did use to work at one point), but back</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> * then I remember some VC++-specific trouble with `bind()` resolution.  Possibly it&#39;s related to the above.</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> * Anyway, use `bind_ns` as needed to get around any such compile errors.</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> *</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> * Note: Knowing of this phantom `bind()` that&#39;s magically available sans qualification, I also tried to use</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> * unqualified `cout` and `endl` in the same context but thankfully got the expected errors in clang saying</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> * these identifiers do not exist but suggesting the use of `std::cout` and `std::endl`.  So, at least it&#39;s not</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> * all of `std` being forced on the code.</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment"> *</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment"> * @todo Investigate deeply the cause of the strange behavior with unqualified `bind()` and others described</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"> * above this line in the source code.</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment"> */</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="keyword">namespace </span>bind_ns = boost;</div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span> </div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment">// Free functions.</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment"></span> </div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment">/**</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment"> * Helper that takes a non-negative duration of arbitrary precision/period and converts it to</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment"> * #Fine_duration, rounding up.  Also, the input type&#39;s `max()` is translated to `Fine_duration::max()`.</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment"> *</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment"> * @tparam Rep</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment"> *         See `boost::chrono::duration` documentation.</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment"> * @tparam Period</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment"> *         See `boost::chrono::duration` documentation.</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment"> * @param dur</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment"> *        A non-negative duration (or assertion trips).</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"> * @return See above.</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"> */</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Rep, <span class="keyword">typename</span> Period&gt;</div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><a class="code hl_typedef" href="namespaceflow.html#a48799f1263cdeedec125be51a3db2b79">Fine_duration</a> <a class="code hl_function" href="namespaceflow_1_1util.html#aa60d3ba517b5f5cf408faa92d269256a">chrono_duration_to_fine_duration</a>(<span class="keyword">const</span> boost::chrono::duration&lt;Rep, Period&gt;&amp; dur);</div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment"></span> </div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment">/**</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment"> * Helper that takes a non-negative duration of arbitrary precision/period and converts it to</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment"> * #Fine_duration, rounding up; then adds it to `Fine_clock::now()` and returns the result.</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment"> * Also, the input type&#39;s `max()` is translated to `Fine_time_pt()` (Epoch-valued -- i.e., zero-valued -- time point).</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment"> *</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment"> * @tparam Rep</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment"> *         See `boost::chrono::duration` documentation.</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment"> * @tparam Period</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment"> *         See `boost::chrono::duration` documentation.</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment"> * @param dur</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment"> *        A non-negative duration (or assertion trips).</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment"> * @return See above.</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"> */</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Rep, <span class="keyword">typename</span> Period&gt;</div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><a class="code hl_typedef" href="namespaceflow.html#a9d9cc2eeb10d398cff5591d446b763b8">Fine_time_pt</a> <a class="code hl_function" href="namespaceflow_1_1util.html#a5488415feb5570a6551892a7bdfeeec4">chrono_duration_from_now_to_fine_time_pt</a>(<span class="keyword">const</span> boost::chrono::duration&lt;Rep, Period&gt;&amp; dur);</div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"></span> </div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment">/**</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment"> * Helper for FLOW_UTIL_WHERE_AM_I() that, given a pointer/length of a string in memory containing a path, returns</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"> * a pointer/length into that same buffer that comprises the postfix</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment"> * just past the last directory separator or (if none exists) to all of it.</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment"> *</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment"> * ### Rationale for taking and returning #String_view this way ###</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment"> * There are 2 other alternatives.  One is essentially to take `std::string` (or #String_view) and return new</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment"> * `std::string` (or some variation).  That is un-great, because the main use case is to use this at log call sites,</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment"> * and creating temporary `std::string`s is best avoided; the ability to simply return a pointer into existing memory,</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment"> * -- particularly since it is likely to come from `__FILE__` (which is in static memory) -- might represent</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment"> * significant perf savings.  So that leaves either the alternative we chose or a variation (which, historically, used</span></div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="comment"> * to be the case) which is to take a `const char*` and return same, into that memory.  The latter is an acceptable</span></div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment"> * approach.  #String_view, by comparison, does involve storing an extra bit of data, namely the length stored inside</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment"> * #String_view.  We stipulate this is negligible in terms of RAM and copying costs when compared to doing same with</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment"> * the pointers alone... but what&#39;s the advantage?  Answer: it may be small; but in order to search for the right-most</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment"> * dir separator character, one needs to internally find the NUL (a/k/a `strlen()`); with #String_view it is already</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment"> * available, so the linear search is unnecessary.  Doesn&#39;t it cost cycles to set the length though? you ask.</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="comment"> * Answer: Not if one constructs the `#String_view`s involved cleverly.  To wit:</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment"> *</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="comment"> * ### Instructions on how to best construct `String_view path` from `__FILE__` ###</span></div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span><span class="comment"> * For max performance, do it in the same way as recommended when setting log::Msg_metadata::m_msg_src_file.</span></div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment"> * Spoiler alert: Use `sizeof(__FILE__)` to obtain a compile-time length.</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment"> *</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment"> * ### `constexpr` ###</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment"> * Update: This function is now `constexpr`, so `path` must be known at compile-time; hence the above instructions</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment"> * (while still valid) apply in a different way.  The raw performance doesn&#39;t necessarily matter (since it&#39;s &quot;executed&quot;</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment"> * by the compiler now).  However, following those instructions (1) will help make `constexpr`ness easier to achieve</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment"> * (as the NUL-terminated #String_view ctor is less likely to be effectively `constexpr` depending on compiler; while</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment"> * the pointer+length ctor is more likely so); and (2) is good for perf in case `constexpr`ness is</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment"> * dropped in the future.  It&#39;s less fragile is the point.  Anyway, just do it!</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment"> *</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment"> * @param path</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment"> *        String containing a path from a `__FILE__` macro.  See instructions above for max perf.</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span><span class="comment"> * @return See above.</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment"> */</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="keyword">constexpr</span> <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">String_view</a> <a class="code hl_function" href="namespaceflow_1_1util.html#a13c3363efdf0d04b04b12ca7487d368c">get_last_path_segment</a>(<a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">String_view</a> path);</div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment"></span> </div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment">/**</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment"> * Helper for FLOW_UTIL_WHERE_AM_I(), etc., that, given values for source code file name, function, and line number,</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment"> * returns an `std::string` equal to what FLOW_UTIL_WHERE_AM_I() would place into an `ostream`.</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment"> *</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment"> * For rationale of using #String_view instead of `const char*` for the string args see similar reasoning in</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment"> * get_last_path_segment() doc header.  See also practical instructions on how to performantly obtain these args, in</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment"> * the doc header for `ARG_file` for FLOW_UTIL_WHERE_AM_I_FROM_ARGS().</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment"> *</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment"> * @param file</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment"> *        See `ARG_file` in FLOW_UTIL_WHERE_AM_I_FROM_ARGS().</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment"> * @param function</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment"> *        Full function name, as from `__FUNCTION__`.  See instructions above for max perf.</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment"> * @param line</span></div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment"> *        Line number, as from `__LINE__`.</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span><span class="comment"> * @return String `X` (suitable for, for example: `std::cout &lt;&lt; X &lt;&lt; &quot;: Hi!&quot;`).</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment"> */</span></div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span>std::string <a class="code hl_function" href="namespaceflow_1_1util.html#a3a33fa903d51cbe124781544eaf0c4bc">get_where_am_i_str</a>(<a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">String_view</a> file, <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">String_view</a> function, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> line);</div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span> </div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span>} <span class="comment">// namespace flow::util</span></div>
<div class="ttc" id="acommon_8hpp_html"><div class="ttname"><a href="common_8hpp.html">common.hpp</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html"><div class="ttname"><a href="namespaceflow_1_1util.html">flow::util</a></div><div class="ttdoc">Flow module containing miscellaneous general-use facilities that don't fit into any other Flow module...</div><div class="ttdef"><b>Definition:</b> <a href="basic__blob_8hpp_source.html#l00028">basic_blob.hpp:29</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_a13c3363efdf0d04b04b12ca7487d368c"><div class="ttname"><a href="namespaceflow_1_1util.html#a13c3363efdf0d04b04b12ca7487d368c">flow::util::get_last_path_segment</a></div><div class="ttdeci">constexpr String_view get_last_path_segment(String_view full_path)</div><div class="ttdoc">Helper for FLOW_UTIL_WHERE_AM_I() that, given a pointer/length of a string in memory containing a pat...</div><div class="ttdef"><b>Definition:</b> <a href="util_2detail_2util_8hpp_source.html#l00054">util.hpp:54</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_a3a33fa903d51cbe124781544eaf0c4bc"><div class="ttname"><a href="namespaceflow_1_1util.html#a3a33fa903d51cbe124781544eaf0c4bc">flow::util::get_where_am_i_str</a></div><div class="ttdeci">std::string get_where_am_i_str(String_view file, String_view function, unsigned int line)</div><div class="ttdoc">Helper for FLOW_UTIL_WHERE_AM_I(), etc., that, given values for source code file name,...</div><div class="ttdef"><b>Definition:</b> <a href="detail_2util_8cpp_source.html#l00027">util.cpp:27</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_a5488415feb5570a6551892a7bdfeeec4"><div class="ttname"><a href="namespaceflow_1_1util.html#a5488415feb5570a6551892a7bdfeeec4">flow::util::chrono_duration_from_now_to_fine_time_pt</a></div><div class="ttdeci">Fine_time_pt chrono_duration_from_now_to_fine_time_pt(const boost::chrono::duration&lt; Rep, Period &gt; &amp;dur)</div><div class="ttdoc">Helper that takes a non-negative duration of arbitrary precision/period and converts it to Fine_durat...</div><div class="ttdef"><b>Definition:</b> <a href="util_2detail_2util_8hpp_source.html#l00042">util.hpp:42</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_aa60d3ba517b5f5cf408faa92d269256a"><div class="ttname"><a href="namespaceflow_1_1util.html#aa60d3ba517b5f5cf408faa92d269256a">flow::util::chrono_duration_to_fine_duration</a></div><div class="ttdeci">Fine_duration chrono_duration_to_fine_duration(const boost::chrono::duration&lt; Rep, Period &gt; &amp;dur)</div><div class="ttdoc">Helper that takes a non-negative duration of arbitrary precision/period and converts it to Fine_durat...</div><div class="ttdef"><b>Definition:</b> <a href="util_2detail_2util_8hpp_source.html#l00031">util.hpp:31</a></div></div>
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<div class="ttc" id="anamespaceflow_html_a48799f1263cdeedec125be51a3db2b79"><div class="ttname"><a href="namespaceflow.html#a48799f1263cdeedec125be51a3db2b79">flow::Fine_duration</a></div><div class="ttdeci">Fine_clock::duration Fine_duration</div><div class="ttdoc">A high-res time duration as computed from two Fine_time_pts.</div><div class="ttdef"><b>Definition:</b> <a href="common_8hpp_source.html#l00416">common.hpp:416</a></div></div>
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